It is a matter of great concern for, in particular, women to maintain healthy and beautiful skin. However, skin conditions are continuously affected by various factors including humidity, UV-light, cosmetics, aging, diseases, stress, eating habits, etc. which result in various skin troubles, for example, weakening in skin functions, aging of the skin. Among these troubles, wrinkles are caused by the aging of the skin due to ageing and photo-aging due to the exposure of the skin to sunbeams. That is, cells protecting dermal fibers are reduced and contracted with ageing or due to the exposure to sunbeams. In particular, collagen fibers are seriously lost and, as a result, the degradation of the derma (i.e., true skin) and the decrease in the subcutaneous fatty tissue accelerate the skin aging, thus causing wrinkles, sags and decrease in skin elasticity.
There have been proposed various compositions and methods for inhibiting or treating these aging phenomena such as wrinkles (for example, JP-A-62-185005, JP-A-62-502546, JP-A-2-72157, JP-A-2-288822, JP-A-7-41419, JP-B-6-510542; the term "JP-A" as used herein means an "unexamined published Japanese patent application", and the term "JP-B" as used herein means an "examined Japanese patent publication"). However, none of these techniques can achieve any satisfactory wrinkle-care effect. Therefore, it has been required to develop a skin cosmetic which has an excellent wrinkle-care effect.